Its famous four-letter logo and revolutionary system of profit-sharing - the "divi" - made the Co-op a high street institution, and generations of schoolchildren have been taught that it began in a humble store on Toad Lane in Rochdale.

Now two amateur historians claim the history books are wrong: the cooperative movement was born nearly 240 years ago in a barely-furnished cottage in Fenwick, East Ayrshire, when local weavers manhandled a sack of oatmeal into John Walker's whitewashed front room and began selling the contents at a discount. It is here, according to a document they unearthed, that the world's first co-op was founded, 230 miles north of the accepted home of the Co-op.

Fenwick's pre-eminence has been overlooked, locals say, in favour of the English town where the Rochdale Pioneers opened their store 83 years later.

The metropolitan borough in north-west England has long boasted of its association with the 28 mill workers who opened their store in 1844, devising the "principles" which became the model for cooperatives worldwide.

A sign on the railway bridge above the A664 leading into the town from the M62 states: "Rochdale: birthplace of cooperation", while the council's website describes the town as the "home of the worldwide cooperative movement".

Yet it seems that movement actually began on March 14 1761, when a group of self-employed weavers gathered secretly in the village of Fenwick, a straggling line of cottages, small shops and old coaching hotels near Kilmarnock which has changed little.

Written in a firm, precise hand, the yellowing document the 15 men signed bound members to be "honest and faithfull to one another ... and to make good & sufficient work and exact neither higher nor lower prices than are accustomed".

It was a revolutionary move. Fenwick survived on tweed and muslin weaving, shoemaking and farming; its tradesmen dependent on patronage by the local elite.

"Cooperation has been around since the year dot, but making it official was different," said John McFadzean, who researched the weavers' history with fellow amateur historian John Smith. "Getting the very much lower working class to fend for themselves, and having the ability to set up the infrastructure to run a documented cooperative was quite a feat ... no one has anything like it predating this."

'Being in need'

Records show the society quickly began lending money to needy members and their families - making it, argue both men, the first recorded credit union. Original records, now in the National Library of Scotland, record short-term loans of 10 and 12 shillings to members, at a flat rate of 5%. One accounts sheet from 1764 records: "Given to Margaret Mitchel at Finnick being in need ... 1s."

The weavers' society began by buying and sharing materials and looms, but in 1769 branched out into food and "victuals", first buying a sack of oatmeal wholesale to sell in smaller quantities at cut price. Savings were divided among the members - a measure Mr Smith insists was a prototype "divi" or dividend.

Those innovations spawned other initiatives; a cooperative subscription library was founded in 1808, and an "emigration society" to help villagers make new lives in the New World. In the early 1800s, the villagers established what became known as the "Fenwick parliament", open meetings to debate local affairs held at the water pump, strategically located at a crossroads.

"It was conceived somewhat secretively," said Mr McFadzean. "They posted lookouts so they could see anyone who was coming. Landowners disapproved of the workers gathering, and taking their future into their own hands, becoming more organised and self-sufficient."

In 1942, a little-known film by the Scottish Co-op said co-ops sprang up in Greenock and Glasgow in imitation of Fenwick. But the Rochdale Pioneers, in the midst of the urban poverty of the industrial revolution, were better organised and better able to directly influence the modern cooperative movement.

Next level

"Fenwick's fate was its location and the lack of infrastructure for it to grow, but there's no getting away from the fact that the principles and the key operational modus operandi were established here," said Mr McFadzean. "It was emulated, and the difference is that one of the emulators took it to the next level. There's no harm in that, but it's as if the whole history started from that point."

The Fenwick Weavers Society finally folded in 1873. It had been left with a handful of members, partly a victim of its popular emigration society. By the early 1870s, Fenwick's population had fallen from 2,000 to 500, dispersed to New Zealand, Australia, Canada, South Africa and the United States. That spread its influence worldwide. Some years after the last surviving weaver, Matthew Fowlds, died aged 100 in 1907, his son Sir George Fowlds became minister of labour in New Zealand.

Virtually ignored in Britain, it has been left to others to commemorate the weavers' achievements. Matthew Fowlds' loom is in Auckland museum, New Zealand, while on the University of California campus at Berkeley, California, there is the "Fenwick Weavers" housing cooperative for students.

Fenwick campaigners are pressing the lottery and the Co-operative Society to help build a heritage centre in the village, and are due to meet senior officials in the Co-operative Society this month. Their campaign has won support from the local council, Scottish politicians, and the Co-op itself - its historians acknowledge that Fenwick was the first proven cooperative, as does Rochdale council. "We want Fenwick to get true recognition for what it achieved," said Mr Smith.

Backstory

Cooperatives began in 18th century Britain when members pooled their income to buy materials and food. In 1844, mill workers in north-west England set up the Rochdale Equitable Pioneers Society and devised eight principles of cooperation: open membership; democratic control; distributing profits to members in proportion to their spending; paying small amounts of interest on capital; political and religious neutrality; cash trading, no credit; promotion of education; and quality goods and services. Co-ops today include the UK's largest independent travel company; account for two-thirds of Kenyan coffee production; involve 2 million farmers in South Korea; produce a third of Canadianmaple syrup, 95% of New Zealand butter, and $117bn of business in the US. The International Cooperative Alliance estimates there are more than 800 million members worldwide.